Objective lens actuator having a high degree of design freedom

摘要

A structure has a focus coil wound or affixed on sides of a lens holder holding an objective lens and two or more permanent magnets spaced from each other and facing the focus coil with their magnetic poles directed in the same direction with respect to one side of the focus coil, wherein the density distribution of the magnetic flux passing through the side of the focus coil facing the permanent magnets has two or more maximum points. This allows for a large assembly error, or tolerance, and reduces inclination of the optical axis in an objective lens actuator used in the optical pickup of various kinds of optical disk devices.